KTP (KTiOPO4) is a nonlinear optical crystal,
which possesses excellent nonlinear and electro-optic
properties.It has large nonlinear optical coefficients
and wide angular bandwidth and small walk-off angle,etc.which
make it suitable for various nonlinear frequency conversion
and wave guide application.
Due to very high effective nonlinearity
(d eff ~8.3xd 36 (KDP)at 1.06 µm) and excellent optical
properties,KTP perfectly suits as lasing material in various
applications .The phase matching range of KTP crystal lies
in 0.99-3.3 µm region .This allows us to use KTP as
an intracavity and extracavity frequency double for the
most commonly used lasers,such as Nd:YAG,Nd:Glass and Nd:YLF
| Physical
and Optical Properties |
| Crystal structure |
Orthorhombic,
point group mm 2 |
| Melting point |
1172°C incongruent
|
| Cell parameters |
a=6.404Å, b=10.616Å,
c=12.814Å, Z=8 |
| Curie point |
936°C |
| Mohs hardness |
~5 |
| Density |
3.01 g/cm 3 |
| Color |
colorless |
| Hygroscopic susceptibility |
no |
| Specific heat |
0.1643 cal/g.°C |
| Thermal conductivity |
0.13 W/cm/°K |
| Electrical conductivity |
3.5x10 -8 s/cm (c-axis,
22°C, 1KHz) |
| Transmitting range |
350nm~4500nm |
| Refractive indices |
|
n x |
n y |
n z |
| 1064nm |
1.7377 |
1.7453 |
1.8297 |
| 532nm |
1.7780 |
1.7886 |
1.8887 |
| Absorption coefficients |
a < 1%/cm @1.064 µm
and 0.532 µm |
| Phase matchable range |
0.984 - 3.4 µm |
| Therm-optic coefficients |
dn x /dT=1.1x10-5/°C,
dn y /dT=1.3x10-5/oC, dn z /dT=1.6x10-5/°C |
| Nonlinear optical coefficients |
d 31 =2.54pm/V, d 31 =4.35pm/V,
d 31 =16.9pm/V
d 24 =3.64pm/V, d 15 =1.91pm/V at 1.064 mm
d eff (II) ≈ (d 24 - d 15 )sin2 f sin2 q - (d
15 sin2f + d 24 cos2 f )sin q |
| Electro-optic coefficients
|
|
Low frequency(pm/V) |
High requency(pm/V) |
r 13
r 23
r 33
r 51
r 42 |
9.5
15.7
36.3
7.3
9.3 |
8.8
13.8
35.0
6.9
8.8 |
| Dielectric constant |
e eff =13 |
| Sellmeier equations |
n x 2 =3.0065+0.03901/(
l 2 -0.04251)-0.01327 l 2
n y 2 =3.0333+0.04154/( l 2 -0.04547)-0.01408 l 2
n z 2 =3.3134+0.05694/( l 2 -0.05658)-0.01682 l 2 |
| Capabilities
|
| 1)Aperture: |
1x1 ~ 10x10mm |
| 2)Length: |
0.05 ~ 20mm |
| 3)Phase Matching Angle:
|
Determined by different
homonic generartion
typical θ=90°; φ=23.5° for SHG 1064nm
|
| 4)Phase matching type: |
Type II |
| 5)Typical Coating: |
a) S1&S2: AR @1064nm
R<0.1%; AR @ 532nm, R<0.25%.
b) S1: HR @1064nm, R>99.8%; HT @808nm, T>5%
S2: AR @1064nm, R<0.1%; AR @532nm, R<0.25%
Different coating specification upon customer request.
|
| Typical
Specification and Tolerance |
| 1)Angle tolerance: |
Δθ < ±
0.5°; Δφ < ± 0.5° |
| 2)Dimension tolerance: |
(W ± 0.1mm) x (H
± 0.1mm) x (L + 0.2mm/-0.1mm) |
| 3)Flatness: |
λ/8 @ 633nm
|
| 4)Scratch/Dig code: |
better than 10/5 Scracth/dig
per MIL-O-13830A |
| 5)Parallelism: |
< 20 arc seconds
|
| 6)Perpendicularity: |
< 5 arc minutes |
| 7)Wavefront distortion: |
< λ/8 @
633nm |
| 8)Clear aperture: |
> 90% central
area |
Notes:
To inquiry or order a finished
KTP crystals, please specify the specification listed above,
we kindly request engineering drawing to specify orientation,
Please consult us for the designs if you're sure about the
phase matching angle for others' special application.
Fig. 1 represents Type
2 SHG tuning curve of KTP in x-y plane. In x-y plane the
slope d(Dk)/dq is small. This corresponds to quasi-angular
noncritical phase matching, which ensures the double advantage
of a large acceptance angle and a small walk off

Fig.1 Fig.2
Fig. 2 represents Type
2 SHG tuning curve of KTP in x-z plane. in x-z plane the
slope d(Dk)/dq is almost zero for wavelengths in the range
1.5-2.5 m m and this corresponds to quasi-wavelength noncritical
phase matching, which ensures a large spectral acceptance.
Wavelength noncritical phase matching is highly desirable
for frequency conversion of short pulses.
Figures 3 and 4 show the
phase matching angles for OPO/OPA pumped at 532 nm in x-y
and x-z plane respectively. As a lasing material for OPG,
OPA or OPO, KTP can most usefully be pumped by Nd lasers
and their second harmonic or any other source with intermediate
wavelength, such as a dye laser (near 600 nm).

Fig.3 Fig.4